Manual loading hoist for trucks



A. E. HANSEN MANUAL LOADING HOIST FOR TRUCKS Aug. 3, 1937.

Filed Aug. 4, 1936 2 sheets -sheet l Aug. 3, 1937. A. E. HANSEN2,088,643

' MANUAL LOADING HOIST FOR TRUCKS' Filed Aug. 4, 1956 2 Sheets-Sheet 2Er n gwucm I Arthur E. Hansen qmz'. i

Patented 3', 1937 MANUAL LOADING nors'r FOR muons Arthur E. Hansen,Seattle, Wash, assignor to Young Iron worka'seattle, Wash, 2.corporation of Washington Application August 4, 1936, Serial No. 34,153

3 Claims.

My invention relatesuto load hoists for use on trucks, to lift heavyloads from ground level up to the levelof the floor of the truck, and tolower such loads. My present invention is an improvement upon my PatentNo. 1,929,112.

In that patent I disclosed such a hoist which was both power operatedand manually operated. In the power operated unit the load is alwaysunder control through the hydraulic unit employed. Power units asdisclosed in my previous patent are entirely dependable andsatisfactory,

but require special installation, and the cost of the hydraulic unit iscomparatively large. It is therefore necessary to provide such a hoistwith manual operating means for certain installations whereit isimpracticable to install power means, either because of the first costor because of the difiiculty of installing thepower unit.

In the manually operated form it was intended that the load should becontrolled through a. ratchet and brake. In practice,,however, it wasfound that operators would become careless, the

brake would be imperfectly set, and when theratchet dog was thrown outthe load would begin to drop and could not be caught by the brake.Furthermore, the crank handle employedjto lift the load would sometimesbe left in' place, and when the load started to lower, would begin torotate rapidly'and would constitute a source of danger to the operator.It is absolutely essential that such a manual hoist have meansincorporated in it to prevent the load running away and dropping, fornot only is this dangerous to the operator, as pointed out above, but inmost instances the load will be damaged or destroyed.

It isa general object of the present invention to provide manual meansfor hoisting, and lowering such a load in conjunction with a truck bodyby means of which the load is at all times under perfect control, andcan never drop accidentally, being always held automatically at anygiven elevation or position unless manually operated to raise or lowerit, and being then automatically held in any new position.

A further object is to provide mechanism of the general characterindicated, which shall be simple, which will make it possible to employsimple spur .gears for power reduction in the hoist, and which can bereadily applied as a unit to the truck body, and which will be capableof operation by unskilled operators or truck drivers, and which,moreover, will be rugged and dependable, and of low cost.

My invention comprises the novel parts, and the novel combination andarrangement thereof with respect to a truck body, as shown in theaccompanying drawings, described in this specification, and as will bemore particularly pointed out by the claims which terminate the same.-

In the accompanying drawings I have shown my invention incorporated in aform which at present is preferred by me.

gure .1 is a. side elevation of the rear end of a truck, showing myinvention incorporated therein;

Figure 2 is a rear'elevation of such a truck,

and of my hoist.

Figure 3 is an axial section through the hoist.

Figures 4 and 5 are respectively a detail section and a detailelevationon the respective lines 44 and 5-5 of Figure 3.

The truck body is illustrated at 9 with its'floor level at 90. It issuitably supported upon the chassis SI of the truck, the rear wheel 92of which-is shown resting upon the ground'at G. A platform 8-issupported at the swinging end of. a. lifting arm I pivotally' mounted atl0 upon the truck body or chassis or preferably upon a frameworkcomposed of spaced plates 2 and 20 which house the hoist unit, and whichare intended to be secured to the chassis or to the truokbody, or both.The platform 8 is ralsed as the lifting, arm I swings upwardly from theround level G to the level of the floor 90 of the truck body. -It issuitably maintained upright while hoisting, as for example by an uprightarm 80,-the platform 8 and arm 80 being pivotally mounted at 8i upon theswinging end of the hoisting arm I, and by a parallel arm 82 which ispivoted at 83 to the upright arm 80, and at the axis of the hand crankC, as will be made clear hereafter. A chain 84 from the upright arm 80to the platform 8 supports the outer end of the platform and permits thelatter to'be swung uD- ward as an endgate when at the level of the floor90. However, in so far as my hoist unit is con-- cerned, the platformmay be of any type and may,

be otherwise supported and guided for movement between its elevated andits lowered position; the presentinvention resides in the manualoperating means for installation upon a truck, to

operate any suitable load elevator.

Formed on the lifting arm I or secured thereto,

of the clutch elements and of the gear train winethe clutch elementsgrip the ratchet wheel. Should the operatorlet goof the crank, theweight operates the clutch element 3, but instead. of the two clutchelements engaging-each other they are arranged to clamp between them a-To effect this clamping action ratchet wheel i. the clutch elements areformed one witha screw element 3i, the other with a nut element 32threaded on the screw element 3 l, and the clutch element 30 is formedwith a hand crank connection 33, whereon the hand crank C. may be.secured, permanently or temporarily. The crank connection 33 ispreferably polygonal-in shape,

as indicated in Figure 5, whereby a removable hand crank'may fitthereon, Whenthe crank is turned it will tend to turn-this element 3.0

and the nut 32 formed therewith, relatively to the clutch element 3andits screw 3L:

when the hand crank connection 38 is turned in a direction to hoist theplatform 8 the'eifect of the interengaged nut 32 and screw 3| is to drawthe two clutch elements 3 and ill towards each -other. The ratchet wheelI, supported upon and rotatlve about an annular flange 34 of the clutchelement 3, is thus clamped between the two clutch elements, and whentightly clamped rotates with them. A ratchet dog ll upon apivot H nxedto one of the plates, and held in engagement at alltimes by a spring 2,permits the ratchet wheel to turn in this direction,- but preventsreverse movement of the ratchet wheel, and consequently of the platformand its load, if any, will tend to reverse the spur gear train, and torotate the 5 clutch element 3 in a. reverse direction, but the" weightof the crank handle, and indeed the reslstance of the parts,'is ample toeffect sufficient relative movement between the screw II and nut 32 toagain clamp the ratchet wheel between the 5p clutch elements 3 and 8'and to hold the load in its position, especially as the speed ofrotation When'it is desired to lower the load of the gear 15, thusreversed; is high as compared to the speed of rotation of the crankconnec-, tion 33.

the crank handle is turned in the reverse direction, tending to unscrewthe nut 32 from the screw 3i, and to separate the clutch elements-3 and.The load, however tends to rotate the clutch element 3 '6 faster thanthe clutch element a is turned, yet

- there is sufiicient unscrewing action to release the clutch elementsfrom the ratchet wheel l, which" is now held against rotation in the dog.40, and to permit this reverse movement, yet theload can c5. never getaway from the operator,- for if it shouldtend to turn faster it willcause "the clutch'elh ment 3 to move toward and overtake the clutchelement 38, and again to clamp the rawhet wheel 4, which is held inpodtionby the dog 40, and

thus the load would be held in. its position.

-"-In order to insure that the clutch element 3 willfollow the clutchelement-30 I may provide a lug, as for example the set screw 5,projecting inwardly from the crankv connection 33 or otherwiseassociated with the clutch ele n 30, and

where the spur gear train described is preferably. I

engageable with a lug 50 carried by a washer 5i keyed to the shaft 16 oran extension thereof, and held in place by the nut 52. If after reversemovement of the crank connection 33, sufficient to engage the lug 5 withthe lug 50, the clutch element 8 has not followed the movement of theclutch element to, the engagement of the lugs will insure that theclutch element 3 is moved to follow up the clutch element 36, and in adirection to clamp the ratchet wheel 4.

. A guard 8'5 may be employed to surround the axial portion of the crankC, and this may serve as a pivot support for the arm 82, previouslydescribed. This arm may be suitably held upon the guard 85, as forexample by the retainer flange 88- (see Figure 3), which is secured tothe outer plate 2.

-The entire device is compact, the spur gears are the cheapest andsimplestform of gearing to employ, and the entire device may bemanufacturedand'installed as a unit, with little or no fitting .to thetruck. I

' What I, claim as my invention is -1 Incombination with a truck bodyhoist having lifting means to elevate a loading platform from; groundlevel to the level of the truck body floor, a driven shaft coupled tosuch lifting means,

a dr1vingishaft,'a hand crank therefor, an end of one of said shaftsbeing hollow and the other posed between said two friction plates andmutually clamped thereby, through the action of said threads by rotationof said driving shaft injthe hoisting direction or by rotation of saiddriven shaft in the lowering directiomfor rotationwith said shafts inthe hoisting direction, and

, releasable by-rotation of said driving shaft in the loweringdirection; and a dog engaging said ratchet wheel to resist'its rotationin the lowering direction under the influence of the tendency of thedriven shaft to be rotated in the lowering direction by the load on saidlifting means, after rotation of the driven shaft in the loweringdirection has effected clamping of the ratchet wheel between said twofriction plates.

2. In combination with a truck body hoist having lifting means to'elevate a loading platform from ground level to the level of the truckbody floor, a driven shaft coupled to such lifting means, a drivingshaft,'a hand crank. therefonan end of one of said shafts being hollowand the other shaft having an end telescopically received therein, afemale thread formed in said hollow shaft end; a male thread cooperatingwith said female thread and formed on the end of said telescopicallyreceived shaft end, a friction plate rigidly fixed to said driven shaftand facing said driving shaft, 8. second friction plate spaced from andfacing said first clutch plate and rigidly fixed to said drivingshaft, aratchet wheel interposed between said two friction plates and mutuallyclamped :th'ereby, through the action of said threads by rotation ofsaid driving shaft in the hoisting direction or by rotation of saiddriven shaft in the lowering direction, for rotation with said shafts inthe hoisting direction, and releasable by rotation of said driving shaftin the lowering direction, a dog engaging said ratchet wheel .toresistits rotation in the lowering direc-- tion under the influence of thetendency of the driven shaft to be rotated inthe lowering direction bythe load on said lifting means, after rotation of the driven shaft inthe lowering direction has effected clamping of the ratchet wheelbetween said two friction plates, an. abutment projecting radiallyoutward from said telescoping shaft end, and a second abutmentprojecting radially inward from said hollow shaft and engageable withsaid first abutment upon less than a complete revolution of the drivingshaft with respect to the driven shaft in a lowering direction, toeffect positive conjoint lowering rotation of said two shafts while theratchet wheel remains held from such rotation by the dog encagedtherewith.

3. In combination with a truck body hoist having lifting means to swinga loading platform from ground level'to the level of the truck bodyfloor, two parallel arms pivotally connected each by one end to suchlifting means, a pivot connecting the other end of said lower arm to thetruck -body, a gear segment formed on the upper side of said lower armand-concentric with said lower arm truck body pivot, a pinion coupledwith said gear segment, a journal on the truck body for said pinion,pivot means concentric with and surrounding said pinion journalconnecting the other end of said upper arm to the truck body, a hoistingand lowering hand crank, a driving member operated thereby and disposedin alignment with said pinion journal, clutch means between said drivingmember and said pinion operable to transmit lowering and hoistingrotation lowering rotation, and released by lowering rotation of saiddriving member corresponding to lowering rotation of said driven member.

- ARTHUR E. HANSEN.

